Construction of arches has been an important and complicated area of construction throughout history. Currently it is common in both commercial and residential applications to construct arches and archways for both structural integrity as well aesthetic appeal. Arches may be used in a variety of applications throughout the construction process; examples include, doorways, windows, entryways, ceilings, decorative moldings, railings, and other desired locations. In some cases, arches are constructed to aid in support of the structure. That is, in many cases the arch must be structurally sound. In other applications, arches are added simply to provide a desired look.
Seeking structural integrity or decorative features, it is important that the builder construct the arch in such a way that the resulting arch is symmetric and as close to the desired size and shape as possible. Commonly, arches are designed to be a portion of the perimeter of a circle. An arch may include as much as a semi-circle, or as little as a few degrees of the perimeter of a much larger circle. A semi-circle includes 180 degrees of the perimeter while an arch including only a tenth of a degree may appear nearly flat to an observer.
The use of arches in building construction is well known. In both residential and commercial settings, arches or archways add significantly to the aesthetic beauty of the edifice. While arches are often desired for their aesthetic appeal, the construction process required for creating arched openings has traditionally been a difficult process, requiring a significant amount of time and energy from the builder. The resulting quality of the arch is dependant on the skill and experience of the builder. A typical process for constructing an arch includes a framer measuring and cutting support pieces for the desired arch. Often, in order to make multiple copies of an arch, or one arch to a high degree of accuracy, a framer may choose to use a string to draw out a portion of a circle on plywood. After drawing a portion of the perimeter of the circle, the framer has an accurate drawing for cutting. An arch may be described more accurately as a circular arch; that is because an arch or archway is actually a portion of the perimeter of a circle. Thus, a framer is able to define a center of a circle, secure one end of a string to the center of the circle. The string, being a defined length, now represents the radius of the circle, by dragging the free end of the string in a circle, keeping the string taught, a perfect portion of a circle may be drawn. For a small arch representing only a few degrees of the perimeter of the circle, a relatively short string may be used from a short distance away.
This method has obvious limitations. It is not uncommon for a framer to be required to build a large arch or an arch that represents only a few degrees of a circle with a radius of many tens of feet or even hundreds of feet. To use the traditional method on such an arch would require a string of enormous lengths as well as requiring a person to walk relatively long distances for each arch.
As a result, due to the skill and time required to produce highly accurate arches, many arches are constructed poorly. For example, the opening may not be true, it may be off-center, or it may be framed poorly requiring additional supports. The difficulties arising in arch construction are well known, and subsequently many attempts have been made to remedy the situation. Methods describing pre-manufactured arches as well as methods for constructing custom and semi-custom arches have been described. However, a need exists for a method that may be used by experienced and inexperienced builders to be able to quickly calculate the cuts necessary to construct accurate arches, especially when an arch may need to be constructed and exactly repeated multiple times, such as in window construction.
Construction calculators are fairly common and often used by builders in calculating various linear dimensions and areas during the building process. Many universal calculators exist. These typically allow a user to input certain characteristics of a problem and calculate amounts of material or dimensions necessary. An example is a construction calculator allowing a user to input a distance from one floor to the other, and a desired angle, the calculator will then tell the user the number of stairs and the length and height of each stair. Another example may be that of a unit converter; a user inputs measurements in feet and receives a converted number in meters, or a length, width, and height to receive a volume.